php text box enter event

[magpieix]

i was created one text box and autosuggestion in json used php. enter text box input "a" and autosuggestion output "a" related keywords, i was select any one keyword using keyboard "Down arrow or Up arrow" and "Enter" key pressed. the form action GET method post only "a" letter, not selected words. i want selected words post in GET method. please help me.....Notes: Select one key word using "Mouse pointer" and GET method post selected words but key board using wrong answer.